My car is dark grey so I turn my lights on when it's raining and on dull days. Also turn them on in underground car parks.

It only makes sense to put your headlights on when it's dark for any reason. I want others to see me as much as I want to see them!!

It's the law in Illinois also; if the wipers are needed, lights are also!

Yep, its the law!

Ditto that in my part of Illinois!!!

(where to the best of my knowledge it is the law - but even if it isn't I turn my lights on)

A lot of the newer cars have headlights that turn on automatically when the car is turned on. They have done studies that reveal there are less accidents if headlights are on. I always turn mine on in the rain. Although we don't get much rain here in northwest Colorado. (Average rainfall is 7 inches a year.)

It's state law here in Arkansas, but about 50% don't follow it, just like all the other laws.

its a law here in south carolina too. i always have lights on. some do not

That is the key: you turn your lights on to be seen. Many people do not turn their lights on because they can see. It is the law here, but most do not bother. Big mistake. Also, my husband's headlights come on automatically, but not the taillights. Fortunately, he now turns on the lights no longer relying on the machine to do it. It doesn't matter to me if is the law or not, it is just common sense.

It's the law here in VA; the first drops of rain you have to use them. I'm amazed at how many people don't use them until it gets so bad theres' no other choice.